论文标题
同步稳定性分析并增强网格绑定的多转换器系统
Synchronization Stability Analysis and Enhancement of Grid-Tied Multi-Converter Systems
论文作者
论文摘要
在网格故障期间，网格绑定转换器的同步不稳定是一个严重的问题。对于相锁环（PLL）同步转换器，网格故障期间的同步稳定性要求PLL可以与功率网格重新同步。对于满足电网代码规范（例如反应性电流支持），这具有重要意义。但是，在高阻抗弱网格背景下的同步并不总是很容易实现。一方面，由于容易受到输出电流的影响，转换器的端子电压是可变的。另一方面，多个转换器与网格互连之间存在相互作用。因此，可能会发生在网格故障过程中转换器的同步（LOS）丢失。先前的研究调查了LOS单相关Infinite-Bus（SCIB）系统的LOS问题，但大多忽略了多个转换器之间的相互作用。对于多个交换器系统而言，以前解决LOS问题的努力也对此表示怀疑。本文开发了一个多连接器的无限驾驶室（MCIB）系统模型，并通过考虑在网格故障期间考虑多转换器的相互作用来分析LO的根本原因。此外，开发了适用于多转换器系统的FeedForward补偿PLL（FFC-PLL）方法来解决LOS问题。仿真结果验证了该方法的有效性。
Synchronization instability of grid-tied converters during grid faults is a serious concern. For phase-locked loop (PLL) synchronized converters, synchronization stability during grid faults requires that PLL can resynchronize with the power grid. It is of great significance for meeting grid code specifications such as reactive current support. However, the synchronization in the context of high-impedance weak grid is not always readily achieved. On one hand, the terminal voltage of converters is changeable due to being susceptible to the output current. One the other hand, there is interaction between multiple converters interconnected to the grid. Therefore, loss of synchronism (LOS) of converters during grid faults likely occurs. Previous research has investigated the LOS issue of single-converter infinite-bus (SCIB) system, but mostly overlooked the interaction between multiple converters. Previous efforts to address the issue of LOS are also in doubt for multi-converter systems. This paper develops a multi-converter infinite-bus (MCIB) system model and analyzes the root cause of LOS with considering multi-converter interaction during grid faults. Moreover, a feedforward compensated PLL (FFC-PLL) method applicable for multi-converter systems is developed to address the LOS issue. Simulations results verify the effectiveness of the method.
